Abstract: In a servo control system having a coarse control unit and a fine control unit, a differential gain is changed temporarily during a short period at an initial state of fine control to shorten a settling time and to reduce overshoot. The servo control system includes a controlled system including a controlled object and a drive unit, a unit for controlling a speed of the controlled object to move and position the same to or adjacent a reference position, and a unit having a differential control circuit and for controlling a position of the controlled object to position the controlled object to the reference position, after the speed control unit moves the controlled object to or adjacent to the reference position. A differential gain of the differential control circuit is selected from at least two values, a first of which is used at an initial state and a second of which is used after the initial state. The servo control system is applicable to a disc system, a printer, etc.

Abstract: Disclosed is a position detecting method and apparatus which are suitable for detecting the position of a moving body on the basis of the output of a position detector for generating two-phase periodic waves having a phase difference of a quarter period, the method comprising the steps of: comparing either one of the two-phase periodic waves with a predetermined reference value having hysteresis to thereby obtain a roughly estimated position for every half period of the one periodic wave; analog-to-digital converting the two-phase periodic waves and a zero-cross value for every sampling period to thereby obtain a finely estimated position; and detecting the position of the moving body on the basis of the roughly estimated position and the finely estimated position while correcting an error due to the hysteresis at the starting point of the roughly estimated position, by use of the relationship between the roughly estimated position and the finely estimated position.

Abstract: A device for controlling positioning of a movable object includes a system for storing therein a provisional target position for the movement of the movable object, the storing system being arranged to store therein the provisional target position by providing an offset with respect to a final target position at which the movable object is to be finally positioned, and a control unit for controlling movement of the movable object, the controlling unit being effective to move the movable object so that, at least during a particular section of the movement, the movable object aims at the provisional target position, and the controlling unit being also effective to introduce, at a predetermined timing, the final target position so that the movable object is moved while aiming at the final target position.

Abstract: The present invention concerns a numerical control apparatus which automatically processes operations for grid shifting and stores a value resulted from the processing so as to correctly carry out grid-shifting without necessity of the aid of an operator when a numerical control system is newly installed.

Abstract: A workpiece clamp actuator system which includes a clamping mechanism and an induction motor having an output coupled to the clamping mechanism for moving the mechanism between an unclamped position in abutment with a stop and a clamped position in abutment with a workpiece. A motor controller selectively feeds energy from first and second power supplies to the induction motor, the first power supply having an output voltage and frequency selected to obtain rapid initial motion at the clamp, and the second power supply having an output frequency equal to the slip frequency of the motor at rated torque and an output voltage selected to provide full load current, and thus maximum torque, at both the clamped and unclamped positions.

Abstract: An apparatus for positioning a recording or playback head over a rotating recording medium, such as a magnetic disk. When access to a desired track is attempted, the head is quickly moved and placed within a range close to the track under open loop control. When the head enters the range close to the desired track, the head control is switched to servo feed under closed loop control. During the servo feed, the head is moved according to a head position signal representing the actual position of the head, the head position signal being given by a head position detector having a portion moving together with the head. The head is thus directed to a predetermined position according to an error signal corresponding to the deviation of the head position. When the head has passed through the desired position, driving force in the reverse direction is generated and the head is forced back toward the desired position. The head thus oscillates around the desired position but converges to it.

Abstract: A control system for a servomotor, includes a portion for producing a driving speed controlling signal to be applied to the servomotor, a portion for producing a driving amount controlling signal to be applied to the servomotor, and a signal controlling portion for controlling the state of transmission of the driving speed controlling signal and the driving amount controlling signal to the servomotor, the signal controlling portion being effective to establish a first transmission state in which at least the driving speed controlling signal can be transmitted to the servomotor with a predetermined amplification rate and a second transmission state in which the driving speed controlling signal can be transmitted to the servomotor with an amplification rate smaller than said predetermined amplification rate while the driving amount controlling signal can be transmitted to the servomotor with a predetermined amplification rate.

Abstract: An offset compensating circuit in a fine control servo. When the servo loop for an error signal is opened, the error signal is sampled and its positive and negative peaks are found. The average of the positive and negative peaks is determined as an offset signal to be subtracted from the error signal when the loop is closed.

Abstract: A control system for positioning a movable member, includes a first control portion operative to move the movable member at a relatively high moving speed toward a position which is in proximity to a target stop position, the first control portion also being operative to decrease the moving speed of the movable member to a creep speed when the movable member moves from a predetermined deceleration starting position to said position in proximity to said target stop position; a second control portion operative on the movable member, after the creep speed is established, to place the movable member at said target position with a relatively high positional accuracy; a detector for detecting a positional error of the movable member with respect to reference at a time when said creep speed is established; and a third control portion for changing the deceleration starting position on the basis of detection by the detector.

Abstract: A method of returning a movable machine element having a flat dog to a zero point includes advancing the movable machine element in the direction of the flat dog, stopping the movable machine element after a changeover signal (S.sub.D) produced by the flat dog is detected, reversing the direction of the movable machine element, moving the movable machine element a first predetermined distance (L) and stopping it after the changeover signal (S.sub.D) is received again, then moving the movable machine element in the opposite direction a second predetermined distance (l) shorter than the first predetermined distance (L) and stopping the movable machine element, thereafter moving the movable machine element at a low velocity and stopping it at an initial one-revolution signal of a servomotor, which operates the movable machine element, after the changeover signal produced by the flat dog is detected.

Abstract: A control for an electric motor which drives a robotic appendage toward and into engagement with an object. In one embodiment, the control causes the robotic appendage to approach the object initially at a relatively high speed to expedite the work operation and then at a relatively low speed prior to impact to protect the object and the motor. A timer is used to determine when to alter the motor speed.

Abstract: An absolute position detecting system for a servocontrol system which has its operation controlled in accordance with a numerical control program. Resolvers 202 and absolute encoders 110 made rotatable with a servomotor 105, are set at a predetermined revolving ratio so that the absolute positions of operating axes may be detected highly accurately from the revolution outputs of the two. The detecting operations can be performed for the plural operating axes by using one detecting circuit commonly.

Abstract: An NC-EDM method and apparatus wherein a succession of electrical discharges is effected across an EDM gap to effect electroerosive stock removal from the workpiece while the tool electrode is consecutively advanced relatively into the workpiece under NC commands which in a prescribed set define a desired path and extent of the relative advancement. Control is effected to act on the EDM power supply for maintaining parameters of the electrical discharges in a given EDM mode during an initial period of the consecutive advancement of the tool electrode relative to the workpiece. The arrival of the tool electrode at a predetermined position relative to the workpiece spaced by a preselected distance from its final position which is determined by the said extent of the consecutive relative advancement is sensed for switching the parameters of the electrical discharges into another EDM mode and maintaining the switched parameters until the tool electrode reaches the said final position relative to the workpiece.

Abstract: Disclosed is a device for regulating motion of a drive component moving along or about a follower axis in response to linear motion of a master drive driven along or about a guiding axis x. The device includes two sensors for sensing the actual displacement along or about the two axes to produce two pairs of phase-shifted timing signals defining the actual displacements about respective axes. The timing signals are applied to a regulating difference generator which includes a forward/backward counter whose output delivers the regulating difference signal. The output of the counter is coupled to the follower drive. A desired displacement signal for the guiding axis is directly applied to the master drive.

Abstract: A method and apparatus for absolute position measurement for numerically controlled machines is provided. The invention produces a unique measurement signal for all locations within the range of a movable machine member using two measuring devices. Each measuring device produces a unique measurement signal within a portion of the range of motion that cyclically repeats over the entire range of motion. The measuring devices are so arranged that the measurement signal of one completes no more than one more cycle over the range of motion than the measurement signal of the other. The difference between the two measurement signals is unique for all locations and is used to produce an absolute position signal.

Abstract: A system for finely feeding a movable member being movable relative to a stationary member.This fine feed system is constructed such that the movable member is provided with a fine feed mechanism, which includes a screwshaft and a nut member threadably coupled to the screwshaft and capable of being suitably clamped against the stationary member. A control device is provided for causing a driving motor to drive the screwshaft on condition that a detector to regulate the relatively movable range between the screwshaft and the nut member is not in operation, while, for causing the driving motor to operate so that the screwshaft and the nut member can return to original relative positions, on condition that the nut member is not clamped against the stationary member. The fine feed of the movable member can be instantaneously performed no matter where the movable member may be in its movable range.

Abstract: A dual mode, digital servo positioning system controls servo motor current by a processor-generated current control set point in conjunction with velocity feedback. When the motor has advanced to the vicinity of a target position, the processor opens the velocity feedback loop and reduces servo amplifier gain, such that the set point controls motor current without velocity feedback. This open loop condition provides a springy servo response that eliminates oscillation due to small deviations from target position caused by electronic drift or gravity. Position information is provided to the processor by means of quadrature encoded tachometer pulses from the motor.

Abstract: The device can control an electric motor intended to rotate the drive shaft of a movable member, solar protection member, closure member or the like.The control device comprises a pulse generator device and an angular position coder, governed as regards rotation by the drive shaft, provided for supplying a signal permanently to a logic processing unit connected, through the intermediary of an input-output interface, to the terminals of the pulse generator device and of the coder and, through the intermediary of an output interface, to the electric motor. The means for regulating the stopping positions are constituted by switches connected, through the intermediary of an input interface, to the logic processing unit, in order to memorize the desired angular stopping positions in the working memory of the latter. A non-volatile memory is connected to the logic processing unit for safeguarding these angular positions in the case of a cut in the power supply.

Abstract: The disclosure relates to an electronic and hydraulic control system to provide variable speed capability for moving a weapon system carried on an armored vehicle. A weapon system is mounted on a turret assembly for movement in the azimuth and elevation directions. Hydraulic motors and piston-cylinder arrangements actuated by a variable electronic control system are employed to drive the weapon system. Through the desired path the control system permits the weapon system to be driven in two ranges, a normal range which is variable and a high speed range which is constant to provide quick motion to a target when needed.

Abstract: A closed-loop feedback-controlled servo system is disclosed which reduces command-to-response error to the system's position feedback resolution least increment, .DELTA.S.sub.R, on a continuous real-time basis for all operating speeds. The servo system employs a second position feedback control loop on a by exception basis, when the command-to-response error .gtoreq..DELTA.S.sub.R, to produce precise position correction signals. When the command-to-response error is less than .DELTA.S.sub.R, control automatically reverts to conventional control means as the second position feedback control loop is disconnected, becoming transparent to conventional servo control means. By operating the second unique position feedback control loop used herein at the appropriate clocking rate, command-to-response error may be reduced to the position feedback resolution least increment. The present system may be utilized in combination with a tachometer loop for increased stability.

Abstract: In a rotary printer control system, a dual mode servo for controlling the velocity and position of a rotary print wheel and a print wheel carriage is normally operated at a relatively high gain value. When the servo is switched from the velocity mode to the position mode, the length of time the servo remains in the position mode is monitored and, if this exceeds a predetermined maximum time period, the gain of the servo loop is switched to a relatively low value in order to reduce oscillations of the print wheel or carriage about the HOME position. The gain reduction is accomplished by inserting a supplemental R-C network in parallel with the high gain R-C network, and the range or ratios of the relatively high gain to the relatively low gain values is from about 10 to about 30.

Abstract: An induction motor is coupled to a movable load to be positioned. The induction motor has two or more stator windings. Alternating current power is connected to the stator windings to energize the motor. A transducer senses the position of the load. Responsive to the transducer, the alternating current power is disconnected from the stator windings as the motor approaches a predetermined load position. Also responsive to the transducer, a direct current energy storage device is connected to the motor as the motor approaches more closely to the predetermined load position to apply direct current to the stator windings and to stop the motor at the predetermined load position. Preferably, the storage device comprises a capacitor connected in series with a rectifier across two input terminals of the motor and the storage device is connected to the motor by a relay coupled from the junction of the rectifier and capacitor to one of the input terminals of the motor.

Abstract: A driver amplifier circuit for an electromechanical position translator having two coils of substantially equal inductance and resistance is disclosed. The circuit includes an input for a control voltage representing desired translator position and a reference voltage, a very low value reference resistor series connected between the two coils, differentially driven push pull amplifiers connected to drive the coils, and two equal value feedback resistors connected from the reference resistor to inverting inputs of the amplifiers, whereby absolute magnitude of output voltage equals the input voltage plus twice the reference voltage, and wherein zero differential input volts yields zero current flow through the coils.

Abstract: In a dual mode servo for a rotary printer control system for controlling the velocity and position of a rotary print wheel and a print wheel carriage, the analog counterpart of a digital desired velocity multibit character is generated by a bidirectional digital to analog converter so that the analog desired velocity signal has a maximum value range lying both above and below a zero reference level, thereby eliminating the need for additional analog level converting circuitry.

Abstract: A method and apparatus for controlling the return of a movable element of a machine tool to a predetermined grid point by controlling a movable element drive device in accordance with feedback pulses generated while the drive device is being driven to transport the movable element between grid points. The method includes the steps of specifying a position remote from the predetermined grid point by a distance which is less than the spacing between grid points, computing the deviation between the specified position and the current position of the movable element, positioning the movable element at the specified position by driving the drive device on the basis of the computed deviation and the feedback pulses, and driving the drive device at reduced speed to stop the movable element at the first grid point encountered following the initiation of reduced-speed drive.

Abstract: A regulating device for an electromagnetic control element, especially for an internal combustion engine with auto-ignition, is proposed in which a non-linear regulator with preferably a PD characteristic is coupled with a pulse regulator, preferably a two-point regulator with PID characteristic. Of special advantage is the interposition of a limiting device, which allows an increase in the D portion of the non-linear regulator, while at the same time suppressing interference. This results in an excellent control behavoir, especially in the face of small control deviations and in a control element or control circuit afflicted with friction and/or (magnetic) hysteresis.

Abstract: A servo motor system including a position sensor located within the motor air gap to virtually eliminate mechanical compliance in the servo loop. The transducer is of a capacitive type including interleaved capacitive plates and is designed to be substantially insensitive to the magnetic field of the motor.

Abstract: A speed control circuit and position control circuit are connected to a spindle drive motor in a machine tool or the like in order to drive the spindle at a predetermined speed and stop the spindle at a predetermined angular position. When an orientation command is issued while the spindle is being rotated at the predetermined speed by a speed control loop, a speed command signal from a speed command circuit is interrupted, the speed reduced to zero, and an initially set voltage is then employed as a speed command to rotate the spindle by a predetermined amount. Next, a integral value of the actual spindle speed is employed as the speed command to further rotate the spindle by a predetermined amount. When this has been accomplished, a constant bias voltage of a low level replaces the speed command, thereby to rotate the spindle still further by a predetermined amount until a specified portion of the spindle approaches extremely close to the predetermined angular position.

Abstract: A system for stopping a spindle, which is provided in a machine tool, in such a manner that a specified point on the spindle is stopped at a predetermined rotational position. The system includes device for detecting the direction of spindle rotation. When the spindle arrives at a region where it is to be controlled in order to stop at the predetermined rotational position, a position deviation signal is applied as the input signal of a speed control loop for controlling the rotation of the spindle. This signal turns the specified point on the spindle to the predetermined rotational position, in the same direction in which the spindle is rotating, on the basis of the direction signal from the detecting means. That is, the specified point on the spindle is rotated to the predetermined rotational position in a direction which is the same as the direction of rotation during tool operation.

Abstract: Electron-beam stage X-Y positioning instrumentation is provided. The electron-beam stage has a number of metal blocks affixed to its bottom. Fixed orthogonal noncontact gage heads are used to sense the distance of the heads from the parallel faces of a proximate metal block. The position of the metal block vis-a-vis the position of the fixed referenced gage heads yields the X-Y coordinates of the stage. The stage is first coarsely positioned adjacent a preselected block.Thereafter the exact position of the stage is computed from the distances sensed by the gage heads. The electron beam electronics are automatically adjusted to the actual position of the stage thereby eliminating the relatively slow, fine positioning of the stage.

Abstract: Automatic octane measurements are made very rapidly with standard test engine using an all-electronic control that automatically lowers the fuel-air ratio to bring the knock intensity below standard, then automatically adjusts the compression to bring the knock intensity to standard, then intermittently increases the fuel-air ratio, after the first or second intermittent increase permits automatic compensatory compression changes only in the decreasing direction to compensate for departures from standard knock intensity and conducts these compensatory compression changes at a rate too slow for adequate compensation if the fuel-air ratio increase causes a substantial increase in knock intensity, and then indicating the compression ratio reading after the knock intensity remains standard during two to four successive fuel-air ratio increases.

Abstract: Method of programming an electronic processor to control an apparatus in which a tool performs a series of discrete operations on a work piece. Initially a pattern is traced manually by a tracer to reflect working of the tool on the work piece with the processor in "Record" mode and input position and location signals are simultaneously generated and recorded to reflect the relative positions of the tracer and pattern. When programmed, the processor is set in "Playback" mode and output position and location signals are fed to apparatus to position tool on work piece reflecting pattern and tracer positions. For accurate positioning of tool and work piece, pattern is a template with tooling indexes that could be made on template in "Record" mode, if desired.

Abstract: Settling problems of a closed loop servo system are substantially eliminated by switching the servo system into position mode operation only when there is zero position error and zero velocity error. The fast and clean settling is accomplished by digitizing the instantaneous amplitude of the position signal when the difference count has decremented to zero and using that digital value as the address of a square root look up table which provides for each instantaneous amplitude of the position signal a digital signal indicative of the instantaneous velocity required to effect rapid settling at the rest position. The digitized velocity signal is converted to an analog signal by a digital to analog converter for energization of the drive motor.

Abstract: A motor control positioning apparatus and method are disclosed wherein variable duration pulses are fed to a DC motor. After the vicinity of the destination has been reached, the final pulsing stage is initiated, in which a short duration pulse is fed to the motor; position is then checked to determine if forward movement of the driven element has occured; and if movement has not occurred, the pulse duration is increased by an increment which is repeated until movement does occur. Thereupon a new series of such pulses is started; and this cycling continues until destination is reached.

Abstract: A signal generating means including a half-round magnet attached to the spindle of a machine tool and mounted relative to a first reference indicator and a pair of opposingly mounted magnetic switches magnetically coupled to the magnet and mounted to a stationary portion of the machine tool and aligned relative to a second reference indicator for generating a first signal when the first magnetic switch is activated by the magnet, a second signal when the second magnetic switch is activated by the magnet; gating means, responsive to the first and second signals for generating an orient signal to orient the spindle to a reference position and a controller means for supplying to the spindle driving signals during the normal mode of operation and for supplying to the spindle during the orientation mode orient signals to cause the spindle to become aligned to the reference position.

Abstract: A control system for stopping a spindle at a prescribed rotational position having a position control loop for driving a spindle so that a positional deviation between the present rotational position of a specified point on the spindle and a predetermined rotational position at which the specified point is to be stopped, is reduced to zero to stop the specified point on the spindle at the predetermined rotational position. Fine and coarse voltage signals are utilized for the final positioning process.

Abstract: A control for a profiling machining tool, and a method for controlling such a tool. The machine tool includes a sensing head which moves along a template or pattern to produce a signal that causes motors relatively to shift a cutting tool and a workpiece so as to duplicate in the workpiece the profile of the template or pattern. Two sinusoidal signals are generated as a consequence of stylus deflection along orthogonal axes. They are combined to form a single sinusoidal signal which is then variously processed to produce an error signal which causes the motors to operate in directions which tend to reduce the error signal, and to cause the stylus automatically to move along the profile while doing so.

Abstract: A position control system is disclosed for aiming a mobile rocket launcher having positionable axes in the azimuth and elevation planes. The control system has a separate control subsystem for each axis of movement, and each such subsystem includes an initial aiming signal processor providing a course positioning function and a reaiming signal processor providing a fine positioning function. The initial aiming processor receives signals representing a desired position (DP), a feedback signal representing the actual position (AP) updated at predetermined sampling intervals, and an error signal (E) representing the difference between DP and AP. From signals representing AP and E, and a constant representing the stopping time of the launcher mechanism for a given control axis, the initial aiming processor produces a predicted position signal (PP) which represents the position that the launcher will reach upon termination of the actuator drive for that axis.

Abstract: A power driver control circuit (38) provides control signals (44, 46, 48, 50, 52, 54) for switching transistors in a power driver (56) for an electromagnetic actuator (11) of the type used for controlling a servo head (12) in a closed loop servo system. The control circuit includes variable time delay circuits (70, 71) connected to threshold detectors (74, 84) so that dead zones can be created when the servo error signal changes polarity thereby isolating the switches and preventing switch burn-out.

Abstract: A system for performing target acquisition and tracking under the control a human operator. The system has a slewable sensor with a line of sight and includes apparatus for slewing the sensor to align its line of sight with a target, the difference between the position of the target and the line of sight being a line of sight error. A display displays the line of sight error to the operator at either a first or a second magnification, selectable by the operator. The operator uses a control manipulator to generate input signals and supply them to the rest of the system. Circuitry is provided for automatically switching from proportional to proportional-plus-integral control upon changing from the first to the second magnification. Circuitry is also provided for initializing an integrator prior to the switchover from the first to the second magnification to eliminate control transients in the concomitant switchover from proportional to proportional-plus-integral control.

Abstract: An automatic machine for displacing a shaping tool, such as a router, over a work area includes a tool mounting assembly carried by support means such as an articulated arm. The arm is movable by first movement means relative to fixed structure of the machine over the whole work area, while the tool mounting assembly can be moved within a limited zone relative to the arm by second movement means. The movement of the tool mounting assembly (and thus of the tool) is directly measured relative to the machine fixed structure and compared with a required movement to generate an error signal. This signal is fed to the second movement means which endeavors to move the tool mounting assembly as required over the work area.

Abstract: A selectable servo ratio and dual speed centrifuge control apparatus utilizing a plurality of phase-lock loops with selected gain increments to provide motor control from coarse to fine in conjunction with an automatic acceleration and deceleration circuit.

Abstract: A high accuracy control system for driving a motor to move a member. The control system includes feedback means for generating a cyclical signal for providing an indication of the actual position of the member. The accuracy of the feedback means is maximized by introducing a gear mechanism between the motor output and the feedback means. Further provided are means for generating command pulses, each of which is indicative of an increment of commanded or desired movement of the member, and means for generating a command signal indicative of the desired commanded movement of the member. In one mode of operation, the incremental command pulses are multiplied by a factor of K to change the command signal by K increments for each incremental command pulse. In another mode of operation, M number of incremental command pulses are converted to a single incremental pulse, and this single incremental pulse is used to change the command signal by one increment of movement for M number of incremental command pulses.

Abstract: A dual mode servo-system providing improved motion characteristics and improved noise immunity. A relatively movable member is driven by control signals derived from actual velocity feedback signals during coarse mode operation. At the beginning of fine mode operation the actual velocity signal is sampled and used to generate a synthetic velocity signal used to control motion of the member during final deceleration, along with an actual position feedback signal, the synthetic velocity signal having a decreasing magnitude tailored to a particular application. At a predetermined maximum time period, after detent of the member, a time out circuit re-inserts the actual velocity feedback signal.Control signals for the driven member are also derived from the actual motor current by integrating the motor current, the integrated current signals being used to control motion of the member during coarse mode operation only.

Abstract: An analog/digital numerical control system that utilizes analog techniques to process large scale (macro) differences and digital techniques to process small scale (micro) differences. In this manner, advantage is taken of the respective virtues of both analog and digital processing techniques while avoiding the disadvantages associated with the exclusive use of either approach. In addition, a novel tach responsive braking generator is disclosed for particular use in controlling the positioning of high mass heads that is adapted to provide dynamic braking of the controlled machine assembly to accomplish proper positioning without "hunting".

Abstract: A process control system providing a particular control effort function is divided into a primary control effort portion having a primary controller, and a feed back from the controlled process to the primary controller, and a secondary control effort portion having a secondary controller in controlling relation therewith, and receiving its control input from the primary controller. The secondary controller is provided with limits such that it becomes saturated in operation, thereby permitting selective overriding by the primary controller, while utilizing the secondary controller and actuators the maximum practical amount. The arrangement is suitable for use with continuously variable devices or for use with on-off (bang-bang) devices. The particular embodiments illustrated are (1) a bang-bang heater system, and (2) a continuously variable fluid flow control system.

Abstract: A system for positioning a displaceable member with respect to a reference conventionally uses a servo-mechanism having feedback position sensing and speed sensing loops connected to an input of the control path of the servo. Usually, the system operates in two successive phases:- a coarse positioning phase and a fine positioning phase. In the fine positioning phase, both loops are active. Nevertheless, if the reference tends to fluctuate, the accuracy of the final positioning may be less than acceptable. In a system according to this invention, an additional device is provided which, under a threshold value of the output of the position difference sensor, disconnects the speed difference sensor and inserts in the single remaining loop series correcting networks which, in addition to ensuring improved accuracy of the final positioning, also ensures an accurate follow-up of the fluctuations of the reference.